What is the performance impact of a front spoiler?
07-04-06, 12:54 PM
#26
Originally Posted by TheOnesAndTwos
All good ideas and designs, but I think we've gotten away from the original question which was affects under 100mph. Being an areospace engineer I deal with a lot of areodynamics, In my opinion the affects would be negligable at speeds under 100mph. Not to mention when assessing the effects that the front air dam has there are many variables to account for; such as road surface, or even the proximity of the car ahead of you. I don't think that there is much of an effect at such low speeds.
So, my friend and I built a front splitter, and eventually a rear diffuser with some panels to smooth out the bottom of the engine bay. The MR2 has the benefit of being almost perfectly smooth from the rear-1/3rd of the car forward, so smoothing out the underside wasn't much trouble. We started with just the front spoiler, which helped a little bit from 70-90, and a lot from 90+. Later on we added the diffuser and lowered the car as well. After some tweaking of the rear spoiler and front splitter, the difference was impressive. From 70+ the front end was rock solid.
Now, at very low speeds I won't argue that it's not going to be of much use. For instance, these mods would be useless on an autocross, especially just a front splitter without a diffuser/rear spoiler/underbody panels. But on a road course or highway driving I think the difference is enough to make it worthwhile.
07-04-06, 12:58 PM
#27
Originally Posted by boog
it seemed to me that splitters/underbody trays/and diffusers would speed up the air moving under the car because it is trying to squeeze its way out...guess im wrong, but why..
Also, if someone made all the underbody stuff wouldn't they need sideskirts of some sort so the air would not be trying to escape out the side at all...
Also, if someone made all the underbody stuff wouldn't they need sideskirts of some sort so the air would not be trying to escape out the side at all...
Sideskirts aren't necessary to create the low pressure.
07-04-06, 01:28 PM
#28
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Originally Posted by boog
ok here is my first mock up experimental design (that's my disclaimer for people who want to say it looks stupid).....
lol, is that a door sweep?
07-04-06, 03:11 PM
#29
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FYI...
Splitter Theory
This next one is from a very good website on prototype racing/design.
Diffuser
Splitter Theory
This next one is from a very good website on prototype racing/design.
Diffuser
Last edited by Jaye; 07-04-06 at 03:14 PM.
07-04-06, 03:16 PM
#31
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I've read that a rear soiler does nothing until you get around 100 MPH. Most look good, but have no purpose.
07-18-06, 02:52 PM
#32
Originally Posted by John64
I've read that a rear soiler does nothing until you get around 100 MPH. Most look good, but have no purpose.
07-18-06, 04:13 PM
#34
Waffles - hmmm good
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From experience, there doesn't seem to be any adverse aero affects on my 80 GS until I get over ~95 mph.
Above that speed, the front does get light and there is marginal lifting but nothing scary until you get over ~115 mph, then you actually can notice a difference in handling. This is with new shocks, strut inserts, springs, and bushings, so its not any loose suspension bits causing the light feel. I've experienced aero afftects in other cars at these speeds and the RX7 is fairly tame but a front spoiler or dam will improve things at speed but may lose you a mpg or at lower speeds.
Its true that most cars can't benefit from the aero bits until you get ~100 mph give o take 10%. Unless your doing Solo 1 or track events you will very rarely be able to get to these speeds in most parts of the US. Although, texas did raise the limit to 80 and theres Wyoming and other western states where maybe this isn't true. Here in the east coast its very hard to get a clear highway thats smooth enough to do this on.
My 2 cents.
Above that speed, the front does get light and there is marginal lifting but nothing scary until you get over ~115 mph, then you actually can notice a difference in handling. This is with new shocks, strut inserts, springs, and bushings, so its not any loose suspension bits causing the light feel. I've experienced aero afftects in other cars at these speeds and the RX7 is fairly tame but a front spoiler or dam will improve things at speed but may lose you a mpg or at lower speeds.
Its true that most cars can't benefit from the aero bits until you get ~100 mph give o take 10%. Unless your doing Solo 1 or track events you will very rarely be able to get to these speeds in most parts of the US. Although, texas did raise the limit to 80 and theres Wyoming and other western states where maybe this isn't true. Here in the east coast its very hard to get a clear highway thats smooth enough to do this on.
My 2 cents.
09-15-06, 03:11 AM
#35
Originally Posted by RustyRotary
It may not be as difficult as it seems. It's basically just a series of triangles welded to a curved piece of metal.
The diffuser basically guides the air out of the back, slowing it down from the high-speed zone under the car.
There is much to be gained by making this whole set-up. When used in conjunction with a flat underbody and front splitter, it greatly increases the downforce created by the entire underbody, including the front splitter. The peaks of the downforce are at the front splitter and the beginning of the diffuser fins, but everywhere inbetween is a lowpressure zone as well.
Also, the diffuser will reduce drag on the rear of the car. If you're using a rear spoiler, this will further improve the effects of the diffuser as well.
The diffuser basically guides the air out of the back, slowing it down from the high-speed zone under the car.
There is much to be gained by making this whole set-up. When used in conjunction with a flat underbody and front splitter, it greatly increases the downforce created by the entire underbody, including the front splitter. The peaks of the downforce are at the front splitter and the beginning of the diffuser fins, but everywhere inbetween is a lowpressure zone as well.
Also, the diffuser will reduce drag on the rear of the car. If you're using a rear spoiler, this will further improve the effects of the diffuser as well.
